Dehumidification cooling coil units

Studies conducted over the last few decades have shown that active humidity control is required in modern, sealed buildings. These studies investigated humidity control using cooling coils [direct expansion (DX) or chilled water], desiccant dehumidification units, mechanical ventilation devices, and humidification units. Additionally, the use of hygroscopically active materials (such as plaster, brick, and ceramic) to control the relative humidity of the surfaces has been considered. This topic is divided into three sections— cooling coil units, desiccant dehumidification devices, and hygroscopically active materials. 

Humidity control may be accomplished by using cooling coil units, desiccant dehumidification units, and hygroscopically active materials. Effects of most indoor air pollutants are strongly influenced by the... 

Note On large air handling unit systems, consideration should be given to bypassing the cooling coil with part of the return air to minimize the amount of reheat required. With coil bypass, pretreating the outside air for dehumidification may be required. 

The heal of water absorption is of importance in low-pressure gas dehydration and air dehumidification. In such applications, it is common practice to use cooling coils in the absorption zone to remove heat which is liberated. In units used for air conditioning dehumidification, the cooling coils may also serve as packing in the air-glycol contact zone as illustrated in Figure 11-13. 

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